"This is a Forbes family recipe, made by the sack full at this time of year, and always served on a plate for Santa - and a carrot of course for the reindeer! I remember my gran making shortbread in trays, scoring the top with a fork. It was almost soft in the middle but utterly delicious and buttery. The final dredge of sugar after baking gives it the edge. Welcoming and Scottish, and above all, very Christmassy!"

Whip the butter and sugar in a mixer until light and fluffy, then gently and carefully sift in the flour and corn flour. Not whilst the machine is on! Fold in, being careful not to over mix at this stage.

Roll the dough into 2 sausage shapes, about the width of a £2 coin. Wrap in cling film and leave in the fridge overnight.

Using a sharp knife, cut the dough into 1cm-thick discs and lay on a baking tray lined with parchment and bake in pre-heated oven (135°C to 150°C) for 45 minutes, or until they start turning golden at the edges. Allow to cool, then dredge with extra sugar.